Japanese Patent Application Publication No. 2011-184096 and Japanese Examined Utility Model Application Publication No. S57-009240 disclose a conventional cap and container that are configured of a cap portion and a ring portion. The container has a mouth part around which are formed a thread part in the upper portion, an annular bead in the middle portion, and an annular shoulder in the lower portion. The cap portion is screwed onto the thread part of the mouth part. The ring portion is coupled to the bottom of the cap portion through a breakaway part and has elastic pieces that fold back so as to be anchored against the annular bead. The ring portion functions to indicate when the cap portion has been unscrewed (i.e., when the breakaway part has been broken).
Thus, twisting off the cap portion detaches the ring portion from the cap portion at the breakaway part so that the ring portion remains around the mouth part of the container. In this way, the ring portion functions as a tamper-evident band indicating when the cap's seal has been broken.